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hard logarithm question help

the tangent to the graph y= e to the kx at x=3 has equation of e^b x y + 4x=13 find the values of k and b


I tried to use dy/dx of y=e to the kx and got dy/dx= ke to the kx and tried to sub in 3 for the question, then i tried to for the other equation to substitute y as mx+c and substitute the gradient of the other graph in this equation but am still confused
Reply 1
Original post by dwrfwrw
the tangent to the graph y= e to the kx at x=3 has equation of e^b x y + 4x=13 find the values of k and b


I tried to use dy/dx of y=e to the kx and got dy/dx= ke to the kx and tried to sub in 3 for the question, then i tried to for the other equation to substitute y as mx+c and substitute the gradient of the other graph in this equation but am still confused

Can you upload your working?
Reply 2
my data on my phone is quite slow so durijng my working all I have done ke to the kx at x =3 so i sub'ed in 3 so got dy/dx= ke to the 3k then got quite confused on how to apply this to solvefor k and b
Reply 3
Original post by dwrfwrw
my data on my phone is quite slow so durijng my working all I have done ke to the kx at x =3 so i sub'ed in 3 so got dy/dx= ke to the 3k then got quite confused on how to apply this to solvefor k and b

You must realise that your post/formatting are hard to read?
What is the given equation of the tangent?

Why not upload the question/working when it's more convenient?
(edited 3 years ago)
Reply 4
IMG_20210420_131016_1.jpg
Reply 5
The tangent equation part is blurry. Maybe take the photo at less of an angle? But Id start with matching
* the value of the function/tangent at x=3
Then match the gradient of the function/tangent at x=3.
(edited 3 years ago)
Reply 6
IMG_20210420_131858.jpg
Reply 7
So match both the function/tangent value and the function/tangent gradient at x=3. What do you get?

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